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Discussion Starter · #1 ·
I thought I share this upgrade with all of you here on the Home Theater Shack. GR Research doesn't just offer a line of products. We also do design work for many companies that range from crossover design work, to driver design, and even entire product line design. We also design upgrades for many commercial speakers and have upgraded hundreds of them. Upgrades made to our customers speakers can range from subtle to very significant. This is one of the more significant ones.

This one is the VMPS 626R.

Okay, the first thing I did was set these up and take a measurement of them with the adjustable settings just as the owner had them set as per his preferences.



The microphone was set on tweeter axis and at one meter. The input signal was adjusted for a 1 watt input. This is an industry standard. And here is the on axis response.



I had been into a pair of these several years ago and was not surprised by the response that covered a 17db range, but I was surprised by the low output levels. Out of phase cancellations between the drivers were causing a big dip in the upper ranges and also showing some out of phase issues with the woofer. All across the woofers range there was some reduction in output as the first order crossover allowed the mid to play well down in the woofers range.

Next I removed the grill. This grill shrouds the woofer as well as the upper drivers. The mid panel has most of its surface blocked by this device reducing its output in its upper and lower ranges. This grill was called a "wave guide", but technically that is not its function or effect. The green line is with the grill removed.



As you can see output levels came up in several areas. The mid actually doesn't play as high in range with the grill removed as the full size of the mid-range driver is utilized. This slightly reduces some of the cancellation effect of the tweeter and allows the tweeter to play up higher in amplitude.

With the grill on I took a spectral decay measurement. The spectral decay shows a clear resonance in the mid panel being caused by the grill. This is likely a cavity resonance between the surface of the cabinet and the grill. It can be seen in the peaked area of the of the mids output.



Measuring the speaker again with the grill in place I decided to have a look at the effect of the adjustable controls on the back of the speaker. These are adjusted by variable L-pads on the back of the speaker. These are often used in car audio and rarely seen in home audio use as the quality of the signal transfer through these devices is not real good. I brought the tweeter level up shown with the orange line. Then I turned up the mid level shown with the green line. Adjusting the mid level up really brought up the large peak in the 2kH to 3kHz range. This would make that area really bright. I can see why the user had that level turned way down.



Since the response looked much better with grill off, I went back to the grill off and adjusted the controls to get the best response that I could. I got the response to within an 11db spread this way.



I was still surprised at the low output levels across the board. This thing barely averaged 80db. I began to question the output levels on my amp, microphone pre-amp, etc. This really couldn't be right could it? So I grabbed an N1 speaker of mine that was stored in another room and brought it in for a quick measurement. It is the green line.



The N1 measured right where it should at 87db. All was right and accurate. These 626R's really were that down in output.

I then pulled a woofer from the 626R and measured its T/S parameters. My measured parameters matched the measurements posted on Misco's web site. http://www.miscospeakers.com/speakers/LLC62W-8A The woofer had 88db sensitivity. So clearly some of it's output was being reduced by the out of phase effects of the mid. The average sensitivity with some baffle step compensation should get the output of this speaker into the 85db range.

Back to taking measurements I wanted to see what the off axis responses looked like.

Here are measurements taken with the grill off. These are taken at on axis, 10, 20, 30, and 40 degrees off axis.



As seen above the horizontal off axis drops off quite a bit in the upper ranges. This is caused from letting the mid play up so high. It is playing well up into the 9kHz to 10kHz range. In those ranges the off axis will drop off quite a bit. This is a function of the width of the diaphragm. Any time a driver plays up in a range that has a shorter wavelength than the width of the diaphragm then there will be some beaming. And this gets worse the further you move off axis. In this case the diaphragm width is 2 and 9/16" wide. That equals about a 5kHz wavelength.

The poor horizontal off axis response though still could be considered a minor problem considering the frequency response and the out of phase cancellation effects. However, there was an attempt to address the poor horizontal off axis response by reducing the width of the mid panel. The solid grill covering it has an opening that is right at 5/8" wide. It also has a cavity behind it with some foam strips down the sides. This appears to be the source of the cavity resonance that was seen above in the spectral decay. A playing surface that is not as wide will have a wider dispersion. 5/8" is wavelength that is in the 19kHz range. So any dropping off in the off axis will be considerably less.

So here is the horizontal off axis with the grill installed.



The off axis response improves through most of the upper range but the frequency response is much worse. So it is a bit of a mixed bag. What is odd was that the reduced playing surface produced by the narrow slit in the solid grill continued up over the tweeter. The tweeter already had a very narrow playing surface and there was no reason to carry it up over the tweeter. This actually caused the tweeter to act as if it had a much thicker face plate. So as the off axis response reached 30 and 40 degrees off axis the thicker face plate effect of the solid grill blocked some of the diaphragm and reduced output. So with the grill going up over the tweeter it has the opposite effect that it has over the mid. It actually reduces its off axis response.

Not only is the horizontal off axis important in creating an even and consistent room response but the vertical off axis is very important in that regard as well. And the vertical off axis is usually the more important of the two to look at. Side walls are often or can be further away and typically are not bare flat surfaces with no room treatment. Even an average room will have furnishings of some kind down the walls that will diffuse and absorb off axis reflections. The ceiling and floors are a different story. The floors are often carpeted and that helps a lot. Ceilings though rarely have any treatment on them at all. So designing a speaker to have an smooth and accurate vertical off axis is very important. Unfortunately this is where the 626r's really fall apart. The low order crossover allows for a lot of output overlap that is not in phase. The result as a vertical off axis that changes drastically with changes in the vertical height.

Below is the measured vertical off axis that is taken at 1 meter and with the first measurement again taken on tweeter axis. It can be seen as the red line. Each additional measurement is made by moving the microphone up only 4" going from orange, to yellow, and then to green. Note how in areas around 1kHz where the drivers were very out of phase have now become in phase and caused a peak. These measurements were made with the grill on.



As a comparison I used an on axis frequency response measurement of our N1 kit to confirm the accuracy of the set up. Again going back to that speaker for comparison here are the vertical off axis responses taken the exact same way for our N1 kit.



Information on the N1 kit can be seen here: http://gr-research.com/n1.aspx

Likewise I took the exact same measurements on the 626R with the grill off. Peaks and dips tend to move around as arrival times from the drivers flip in and out of phase with one another.



Next up was to look at the impedance curve. This is how the electrical load is seen by the amplifier. First order networks have very little impedance shift and typically look real good from that standpoint. And this one looks pretty good all except for some break up in the 200Hz to 250Hz range. This shows that there is an internal cavity resonance that is effecting the woofer.



The cavity resonance issue is easily solved. There was little to no damping material in the box. A small piece of Blackhole 5 was installed to the left and right of the woofer. No additional insulation was installed. Here are a few pics of the internals.





The tweeter was recessed a little deeper than it needed to be.



And there was no damping material in the top of the box behind the tweeter. This was likely a big contributor to the cavity resonance.



I then removed all of the drivers and wired them with new wiring that was routed out the port hole in the rear. This allowed me to measure the drivers individually to design a new network for them.

The mid use a pair of screws that poked through the diaphragm to allow an electrical connection point. What was odd was that the two screws were installed from the back and stuck out through the front of the driver where a nut was installed for tightening. These screws stick out considerably on the front of the driver. When I disassembled them I removed the screws and installed them from the front so that the extra screw length and nuts would be hidden on the back side and only a clean screw head would be seen from the front side.



The woofer and tweeter were installed using a dull sheet rock screw. The mids used a shinny steel screw that really stood out on the black driver and black cabinet.

The mid cavity was also very densely packed with a very heavy polyfill. This was much denser than what would be ideal for this driver. When I reinstalled it I lightened up on it some.

I then began measuring the drivers and designing a new crossover.

Since I would be dropping the upper crossover point down into a lower range that allowed each driver to operate in way that utilized its strengths and avoided its weaknesses then there would be no need for blocking off part of the mid. The tweeter will be covering the upper ranges in this case and not the mid. And the narrow tweeter has very good off axis response.

Designing a new crossover was pretty simple. I have worked with this mid and tweeter many times before and already knew what to expect of them. And with a minimal amount of baffle step compensation on the woofer the frequency response came up to the 85db range. The out of phase overlapping of the mid was eating up its output with the stock crossover.



I was not happy with the response of the mid though. It was a bit peaky. And having worked with this driver in the past I knew this was not the typical response that I would expect from this mid. The cabinet thickness of this box was 1" thick, and the back side of the drivers holes had not had a radius put on them. So I suspected that some internal edge diffraction could be the source of the problem. Earlier VMPS cabinets were not this thick, and in the case of the 626R the previous cabinets were only 5/8" thick.

So I pulled out the damping material and started moving it around to minimize the edge diffraction. It still looked bad, and I knew this mid was much smoother. I then pulled out all of the thick polyfill and started experimenting with some fiberglass insulation. I laid it in covering all of the sides, top, bottom, and back walls while leaving an open pocket right behind the driver. This did the trick and produced a much smoother response.



It is a little hard to see in the pics but the insulation is back a good 2" or more right behind the driver.



Here is the measured result. The mids response is much smoother now.



It is less than +/-1db over most of its range. I left the tweeters output a little heavy on the very top end because the ribbon tweeter is fairly tall compared to a dome tweeter. The taller diaphragm means that its output will drop off more in the vertical off axis. So the on axis response is adjusted slightly to compensate for the off axis.

Here is the new horizontal off axis response taken the same way as before.



Scroll back up and you can compare this one to the stock crossover. It is much smoother in the off axis than before and there is no need for the old grill that blocked off parts of the playing surface.

Here are the new vertical off axis measurements taken in the same way as before moving the microphone up 4" at a time. The lower crossover points and steeper slopes allow the drivers to stay in phase very well even as changes to physical distances are made. The first 4" upward movement produced a response that is even smoother overall than the on axis response.



The speaker will now produce a very smooth and balanced in room response (baring any room related problems).

The spectral decay is now very clean as well.



The resonance that the grill produced, in the peak that it caused in the mids response, is of coarse no longer there as well. The planar magnetic mid and ribbon tweeter are very fast, or quick to settle, and show very little stored energy compared to other drivers.

The impedance curve shows that more reactive parts are being used to control the response of the drivers, but a pretty smooth curve is maintained. The internal cavity resonance that was in the 200Hz and 250Hz range is no longer there as some fiberglass insulation was used in the top of the box, over the old crossover in the floor of the box, and on the back wall.



Overall this is a completely new speaker with an extremely smooth response. Here is a measurement taken on axis showing 85db sensitivity.



And here again is the same on axis response curve taken of the speaker as received. The sensitivity averaged less than 80db and the response was all over the place.



This new crossover will be made available to anyone that is interested in it. The new crossover design uses much higher quality parts than the stock crossover with Sonicaps, Mills resistors, Erse XQ air core and foil inductors, Erse poly caps and some Gen.2 Sonicaps. The parts come with a new schematic and high quality wire. If you do not want to perform this upgrade yourself then there is someone available and ready to perform the upgrade for you and complete a full install.

I also highly recommend replacing the binding post in the rear of the speaker with tube connectors from Electra Cable.

Here is a pic of the old connectors.



Oddly there was a rectangular shaped hole cut in the back of the speaker for mounting an internal board that the binding post went through. Why the binding posts were not installed right through the back of the cabinet, I do not know. The hole exposed bare MDF all around it. When this was complained about by the owner of this pair a black magic marker was sent out to him so he could color it in.

Here is where the tube connectors can be seen. http://www.electracable.com/tubeconnector.htm

Total cost of all crossover parts, wire, tube connectors, schematic and our support is less than half of what VMPS charged for the TRT cap upgrade for this speaker. Give GR Research a call if interested in this upgrade: 940-592-3400
 

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Discussion Starter · #2 ·
If you guys are into looking at measurements and making comparisons then here are some more for you. This is a group of speakers that I measured for Stereo Mojo when I hosted a small speaker shoot out several years ago. There is some explanation with the measurements up top. All of these were measured in the same way that I measured the VMPS speaker.

http://www.stereomojo.com/Small Spe...omojoSmallSpeakerShootout2007Measurements.htm
 

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:unbelievable:

I'm impressed: that's some really good work you've done Danny and I'm sure the owner is ecstatic now that the speakers truly perform well. I'm guessing your experience led you toward the proper analysis and diagnosis right away. The more I read about quality design from contributors like yourself, the more I'm tempted to delay upgrading until I can afford to replace most of the loudspeakers I currently have.
 

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What an excellent and informative thread.

I don't own these speakers but found it very interesting to see how you improved these speakers so dramatically.

Thanks for posting and educating!
 

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Discussion Starter · #5 ·
The process that I went through with these speakers is typical of any speaker that I evaluate. It has to be looked at as a whole, so I look for problems in many areas. Just another day at the office.
 

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Hey Danny... that is some really neat stuff you fixed up there. Interesting discovery and a shame it wasn't done right to begin with, considering their cost... even though you could probably pick up some used ones on the cheap.

I know Brian is no longer with us and I assume VMPS is no longer in operation. It seems there were always a lot of issues with his speakers. What I don't really understand is what did he think he was hearing... it is obvious he never measured the speakers... and what about all those owners that raved over his speakers (some still do), although there is no doubt issues with all of them if you look at the various designs.

Either way, it is nice to know you can make something out of nothing. :T
 

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Wow, I didn't hear about Brian, I am sad to hear the news.

I have never had the opportunity to hear any of his designs but he was definitely someone I knew about and tried to acquire some of his subs to have a listen. Any true hobbyist of audio would know about VMPS, it was just one of those brands.

My condolences to Brian's family.
 

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Discussion Starter · #8 ·
The owner passed away earlier this year and the business was closed. His health had been on the decline for a while and the business was winding down for some time prior to his death. They really haven't done much for several years.

The guy that contacted me with these 626R's was the third person that has contacted in the last few months wanting help with VMPS speakers in one way or another. I will do what I can to help those that are in need of assistance.
 

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I am the owner of the above speaker in the review. What follows are some observations and comments that hopefully will encourage owners of the same speakers to follow my path, and for those that don't own any to pick up a pair and do the mods suggested.

No review would be remotely complete without mentioning my gratitude to Danny Richie. He is the most gracious, kind, generous and patient individual imaginable. The time he spent in working on the problem goes way beyond any expectations I could have possibly had. The results speak for themselves.

I am posting this review in HTS because I think a lot of combined HT/2 channel users would probably use these speakers the same way. In the first part, I will explain some of the problems encountered in modifying the speakers to accomodate the upgrades. Then I will try as best I can to describe the glorious transformation that Danny engineered.

I bought the speakers new with the TRT cap upgrade and over the years with the help of members of our audiophile society moved, adjusted, tweaked, and did whatever else we could to make them sound as wonderful as the advertising claimed. It didn't happen. Like many of you, I suffer from wifey constraints, and my listening room is complicated by the fact that the back wall is all mirror, giving me a wonderful surround effect whether I want it or not. More on this later.

Music, especially full orchestra pieces, always seemed to lack that gut punch and after really deciding to apply myself in listening, it was obvious that tom toms and tympani were pathetic, along with all other insttuments in the 100 hz range. Despite my best efforts to correct this (boosting the subwoofers, turning the pots this way and that on the 626's, nothing seemed to work to much of a degree. Every time I would go listen to some one else's system I would come home and play the same disc on my system and weep. They were really pathetic, and that is hard to admit when you have dumped so much money into the purchase..
It took a long time to come to grips with the fact I was beyond my ability to fix the problem, and I sat and stewed for way too long before sending the speaker in the article to Danny. Well, you can see for yourself what the problem was. And it wasn't the drivers, as you will see. It was the pathetic (and I am being kind) crossover design.
And once Danny finished the new design and sent it back to me, the hard work began. And I mean hard. It took a lot of mental gymnastics to figure out placement of the components but in the end all worked out for the good.

You see, Danny could design things by keeping components outside the box, but I had to somehow get them all inside, and this turned out to be an interesting task. After the first one, it still wasn't easy, but much faster. And each speaker gained aouut 11 pounds in weight, making it quite the beefy little block.

It probably couldn't be any worse than stock, though. You can see from Danny's pics what the first one looked like. I tried to upload some photos but apparently my files are too large... and I don't know how to correct that.

There were a number of things that needed to be fixed, among them additional bracing, reducing the volume of the box, extending the port tube, rounding the backsides of the mid and woofer holes, and changing the type and volume of insulation. When that was all done the issue became how to put the new crossover in there, if at all. In the end I wound up making three boards, one for each driver, and mounting them in different locations. There is a massive increase in the size (volume) of the much higher level of components that Danny supplies. In the end it was more than worth the effort.

To be fair to Danny I am leaving out some aspects of the construction. If anyone buys the upgrades from him and I verify it I would be more than happy to share with them what I did. Trust me, it will save untold hours and a lot of money and headaches. He deserves to make a little back for the extrordinary time spent on my unit. And, I paid the freight two ways for the prototype, so you save a lot riight there.

OK, enough of that. The bottom line is:how does it sound? Simply stupendous. Let me tell you a little about what I have for equipment because I wanted to test the speakers both in 2 channel and surround. All the CD's I used here are just redbook, no high rez stuff at all. My player, used as a transport, is a highly modified Oppo BD83. The prepro is a NAD T175 and the amp is a 7 channel Wyred4sound 250 wpc into 8 ohms with modified input boards. I have a Wyred DAC and STPSE pre for 2 channel, but I did not use them for the testing to keep things comparable, Besides, I like to play some of the stereo stuff in multichannel; it just sounds better.

Plugged in the "new" speakers, fired it up and tossed in a CD (Bob Marley) and was immediately reminded that I had forgotten to turn off the subs (dual Rythmik 15's). So, grabbing the remote and going into the menu (a little drill down) it was discovered that THE SUBS WERENT' ON! This was the first of many revelations.
As mentioned before, the wife issue can be at odds with the best intentions. I sit 15 feet away from speakers on a 7 foot center, so for testing a chair was positioned 7 feet in front of the drivers. Sitting on a couple of padded barstools (talk about a solid mount!) with the rear of the speakers 37 inches from the rear wall and about 25 degrees of toe in the presense of vocals was not just startling, it was unnerving. The clarity unlocked in the mid and tweeter panel was as though a beach towel had been covering them before. Soundstage? Wider than the room, and before, with the "waveguides" on there was always this diffuse image. While you could move around the room with little change in the apparent center, is was dull sounding. This was different, focused, clear, and with all the cues and sounds present.

Painful though it may be, I had to put them back where they were before, under the watch of the now glaring spouse (this is not her thing, at all). With the same toe angle and the rear 16 inches from the rear wall the bass boost was noticable. The stage depth decreased some, but the width did not diminish. For a quick check I played some brass pieces; instead of 7.6 trombones we now had 76, the Sousaphone no longer sounded like Susan's phone, and trumpets had that glorious blatt with harmonic overtomes that you hear with it live.

I will cover some specifics in a minute, but I wanted to set up the Audyssey system to help for the terrible room acoustics. Before the modifications, activating Audyssey made a huge difference in sound quality, so much so that I quit using the dedicated two channel, as it realy sounded better in the HT rig even though the resolution was less. Oh, how the Audyssey must have strained to correct the errors you can see in the intitial measurements. Now, strangely, while there was some correction, it was very minor and not really a big deal one way or the other, vindicating proper crossover design once again. At this point I did try a little dedicated two channel and all I can say is that it took it to another world.

The biggest thing you first notice is the clarity and resolution. There is no room for the recording to hide. Now the argument may be made that the HT rig is not the highest resolution, and that may be partially true, but upon actual listening the argument becomes very weak. They are that good. And it really makes one wonder why it wasn't this way to begin with.

What follows are my observations of selected cuts I use to review systems. No system is perfect, all miss something somewhere in the spectrum, but when a system doesn't play certain parts I know something is amiss. And some high dollar system have left me very unimpressed. Keep in mind ny strange room with its padded front wall, theater curtain sides (on one covering a wall of glass) and my rear wall of mirror. The comments are based on using the system with the subs turned off; with them on it is another bump up in perception and resolution.

Oak Ridge Boys "Make my life with you" Good range of vocals, especially bass. Before, one could hear the harmony. Noiw each individual singer and placement is very apparent. Close your eyes and listen deeply into the music. You will hear things that were only resolved with headphones before.

Alley Cats "Only You" This cover of the classic Platters tune makes the hair on my neck stand up now, you are on stage with them.

Bob Marley "Buffalo Soldier". Gotta hear it to believe it. Don't need subs to get the gut punching bass now.

Paul Simon "Diamonds on the soles of her shoes". Before, kind of blah. Now, when the drums first come in, tremendous slam like it supposed to be.

Led Zeppelin"Moby Dick" Before, Moby Dickless. Now , the missing tom toms slam the room. With the subs going it is now better than live. 1/2 the music was missing before.

Our Style of Jazz album -Galib Ghalab "Green Dolphin Street". I first heard this on a pair of Tannoy Westminsters powered by a 30 watt push pull tube amp one of the dealer's customers had built. They were about 10 feet from the wall so there was good air. I always thought Tannoy was about as ugly as my grandfather's furniture from the Spanish American war era, and their design was too simple to be any good.Forgive me father for I have sinned. To say the sound was stunning would be a huge understatement. And this cut on those speakers put every musician side to side, front to rear, up and down, in and out and with perfect instrumentation so real it was like ghosts were in the room performing. This sound is still my gold standard. Do the VMPS match it?......Well, do they?...
Nope.Better not, or somebody's in trouble. But they do present the positions in space well and have the same clarity. I didn't listen with the speakers on the bar stools, but I bet if they were out in the room on stands it would be close, minus the weight of the piano that comes through those 15 inch concentrics. And, the VMPS are not the size of a large range and oven. Try that with your wife if you dare.

Rick Nelson "Travelin Man". There is a good vocal intro to this song with the backup singers that varies from strong to non-existant in many systems. Here it is just about perfect, showing the midrange is right on. And now one can clearly delineate very distinctly each of the backup singers instead of just hearing the combined harmony.
Also the outakes on "Hello Mary Lou" which are hard to make out in the "before" iteration are now crystal clear and easy to understand.

Nitty Gritty Dirt Band -Circle be Unbroken II album, cut 19 (Circle...) The eveness of the piano intro, which really sucked before, is now very even and nicely weighted, and the bass riff blooms correctly. Sounds live.

Kenny Rogers "Ruby". I thought he had a gravelly voice on this one before, but kind of mellow. Well, now it is so revealing you can hear each polyp he had affecting his voice. It makes him sound like he is about 85 years old tring to hang onto notes he can't quite nail anymore. Whether this is a good thing or not is open to discussion, but it does show the absolute revealing character of the speaker.

I won't comment too much on female voices for one reason: they all play on either the mid panel or tweeter and about all I do is sit there with my jaw slack. Joan Baez, Eva Cassidy, Elaine Page, Babs, you name it. Doesn't matter if it is only redbook CD, close your eyes and they are 5 feet in front of you without a microphone. Acapella and acoustic are scary real.

The components used in the basic speaker design are actually pretty good and were just crippled by the lack of attention to the crossover design. By using superior design, better caps, coils, and resistors, Danny Richie has worked a miracle of sorts. The MLS cabinets are pretty and it was nice to be able to use them, with modifications. I won't get into the "what price would they compare to?" argument, because it would humiliate many brands. However, this much is true. They hit hard, low(solid into the 30's), the mid and treble drivers outperform any cones for speed and clarity and the soundstage width and depth is startling. Shoulda done this years ago.

If you have a set of these, you have no excuse not to do this upgrade. None.You have no idea how bad they are until you hear in retrospect how bad they were. I love Sousa marches, especially Stars and Stripes. Trombones and piccolo were puny at best before. Bass drum sounded like a trash can and even the subwoofers couln't fill in the hole. Now my chest thumps like it did when I was five and the high school band played it for us. The highs are so clear they test the limits of my aging hearing. The upgrade described here is hands down the single best thing you can to by such a wide margin that anything else is irrelevant. Want a real deal? Buy a pair of these used if you can (caps don't matter, just the drivers) do the mod, and impress everyone with your savy. They play as measured and sound even better. Danny is THE MAN!

I hope this helps a little bit. Listening is even better. I am in So Cal. Let me know if you would like to hear them and I will see if I can work it out.
 

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Nice and detailed write-up Mike... thank you!

It was amazing to see Danny's transformation on those he did.

I wish I had known Danny back when I purchased my RM30's, although I am not sure there would have been a way to get those right, but if there were a way, I believe Danny could have done it.

What surprises me is the number of people who actually thought all these speakers from VMPS sounded good... at least since I have learned the majority of them (I think it was around 100%) of them were seriously riddled with flaws and issues. It makes me wonder what they were listening to... and if they have since figured out what good sound should be.

You were obviously determined and succeeded. Congrats!

Would love to see some pics if you can figure it out. You might try our Image Gallery.
 

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I'll work on those photos. It looks like my files are too big to put in. Does the program resize or do I need to do that first?

As regards the speakers: A good parallel would be car design and interior design. Most people know when they see it if it is right, but they wouldn't have a clue how to do it themselves. And so they exist with imperfection. Sme thing here, you think it sounds good, but you don't really know until you measure it. My experience with the Tannoy's validated that one for me big time.
Just like a pilot, you have to trust your instruments, and how anyone can design a speaker without them is beyond my wildest comprehension.

A friend of mine has an all tube system and some hemp coned speakers (Omega I believe). His system always sounded so mellow and he played The Civil Wars Barton Hollow vinyl on it for me. Totally smitten, I bought the CD (I am a solid state guy all the way, for convenience) took it home and ??? This is how I first knew there were major problems. Now, they actually sound pretty close, but I think I can hear a little deeper into the recording. And that is using my HT prepro, which costs about 1/3 of his preamp alone!

I used most of a 24x30 inch piece of Baltic Birch to make pieces to stiffen and reduce the box size, added two braces, extended the port, wired the drivers directly, point to point wired the crossovers and a whole lot more.
From Danny's initial measurements it was obvious the box was too big for the bass driver. Wouldn't that have been nice to know when Brian was designing the speaker to begin with? Now, it wouldn't have exactly been a Bose cube, but any reduction would help. This is one heavy and inert unit now. They sit on top of my subs, probably not a good idea, but I am led by a ring through my nose, if you know what I mean. However, I listen mostly at 70 db or below and there is some evidence that the apron effect of the sub box helps boost bass a little.

I spent some time this morning revisiting some of the test songs and played more on each album to get a better feel for what I wanted to say. All reviews are opinions of course, but the overall impression is that we now have a truly full range speaker that is evenly integrated. ALL the music and voices are there with no more holes. And a comment on the bass: it does play deeper and stronger than the size would suggest, and not by a small margin. That just leaves me scratching my head when I look at some of the high priced "monitors" that start to run out of steam at around 100 hz.

Fate took me the wrong direction initially, but Danny cured the patient. The end result is truly more than the sum of its parts, and the value is many multiples of its cost. For those that will not have to ship their speakers to Danny and pay all that freight the bargain is just too good to pass up. Now, I've got the music in me once again!

Doing it right is always better than doing it over, but hey, it IS a hobby. And I feel really good about the end result here; just wish it didn't take 5 years or so to get to this point. Proper design, detail, and execution really do work!
 

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Hey Danny... that is some really neat stuff you fixed up there. Interesting discovery and a shame it wasn't done right to begin with, considering their cost... even though you could probably pick up some used ones on the cheap.

I know Brian is no longer with us and I assume VMPS is no longer in operation. It seems there were always a lot of issues with his speakers. What I don't really understand is what did he think he was hearing... it is obvious he never measured the speakers... and what about all those owners that raved over his speakers (some still do), although there is no doubt issues with all of them if you look at the various designs.

Either way, it is nice to know you can make something out of nothing. :T
Actually... Someone has a huge inventory of his speakers up for sale as parts on craigslist. http://sfbay.craigslist.org/search/?sort=rel&areaID=1&subAreaID=&query=vmps&catAbb=sss

http://sfbay.craigslist.org/eby/ele/4177171505.html


I have seen him selling them for the last few weeks. I don't know who it is but I am assuming it is from his estate, but I do know it is from his town, and there are a lot of parts for sale. So if you need some spare parts or want to build up some, now might be the time.
 

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It Is Pat Malaga per this post on audiocircle..."As stated in my cl ad in the sf bay area, I have acquired:152 dyna ribbons,28 FST's,58 cast 6 inch mid woofers,39 stamp frame mids,8 inch,10 inch and 12 inch woofers,15 inch frames, 1 case of neo panels,1 pr rmv60 complete and working well.34 bi pole cabinets,13 tower type cabinets,11 rm 30 cabinets,1 set of rm 60 cabinets ,60 plus LRC's cabinets, a few single cabinets like 626 and rm40. I know it sounds like a little much but these drivers and cabinets can be sold in kit form for now,until I master a few x -over networks-I am working on getting the specs. I have been building custom audio for 30 years and own a car audio shop called Sound Advice in El Sobrante. This was the last of 3 storage units after the "plant" was closed. With a bit of assistance from Shirley,Brians wife I should be able to fill in some missing links and build some sets for clients. Thank you"
 

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I have Danny's QSO626R crossover upgrade for my pair. It made a huge difference in sound quality for the better. I wired the individual drivers externally to the cabinet and connect the crossover external to the cabinet.

When a friend was having issues with his RM50's, I took out the mid panels and installed them in his speakers. Will rebuild the QSO626R's at some point with the replacement Sonigistics panels. They are backup speakers at this point, replaced with Danny's Super V speakers.
 

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It is hard to beat open baffles and that is undisputed. Forced by spousal pressures I lack that option in this house.
And even though my 626's are rear ported and 16 inches from the rear wall, that wall is 2 inches of padding and the speakers are at about a 25 degree angle to it. The shorter delay this should cause isn't legible, at least to me.

I had thought about going outboard with the crossover like you did, but there would be no way to hide it.
Since the volume of the box had to be reduced anyway it was a matter of many layouts and trial runs to see what would fit where. While the box itself is rather large, the enclosure for the mid juts out to the inside in such a way that it is hard to use the space around or behind it, especially with the port tube almost touching the rear wall.

I used point to point wiring, WBT solder, and mounted the x over components on 1/4" Baltic Birch, then isolated them from the box itself with 1/8 inch 40 durometer sorbothane. Enlarging the holes where the lpads used to be made a perfect spot to install Danny's terminals.

I wound up with 14 pieces of 3/4 inch and 3/8 inch Baltic used to both stiffen and reduce box volume, along with front to rear braces. Since the box was 1 1/4 inch mdf to start, it wound up being very heavy. And, I had to purchase a round under bit to bevel the mid and woofer cutouts. In addition, there was the right angle drill attachment I needed to install the x overs.

One difficulty I had which no one else probably will have is that I had coated the inside of the box with Quiet Coat about an eighth inch thick when I first got the speakers. Being uneven made for a lot of work with a Stanley surform and a sharp chisel to get the humps down. Since it was not going to be a perfect surface, I glued the wood pieces in using polyurethane construction adhesive (2 tubes of the 3X; 7x is not that great). I would suppose this did give a constrained layer damping effect; all I can say is that the box is super stiff and has a very dull thud now.

I filled in the hole where the original terminals had been with a piece of 3/4" and painted it gloss black with Testors. It leaves a slight recess, but who cares? It is on the rear. The port tube was more of an issue and I devised a fix to lengthen it by cutting it short, grinding a 1 1/2 " ABS elbow so it would fit, and putting an extension on the other end of the elbow. Reinstalling is a two man job for this portion.

Most of all, I forgot to report on one of the most amazing changes I heard. Why this slipped my mind while writing the main review can only be excused by a senior moment, or Diet Coke overload.

SIBILANTS. We don't need no stinking sibilants! The fact that they were almost non existent anymore missed my perception on the first go around. Then I remembered to check. On some recordings where it sounded like the performer was spitting in your face there was only a slight hiss, on others, it was gone. No wonder it was so easy to listen to now.

I always thought it was either microphone or performer issues that caused that effect. It would now seem to me that speaker design is the biggest culprit. I don't know how Danny did it, but he did do it. I have heard a/b speaker demos where one brand had strong sibilants and the other did not, side by side. I always put it off to less resolving power or something like that it the one less audible. Apparently it was just bad design. The education process continues. One of the best recordings to judge this with male voices is Chad Mitchell Trio the Mercury years on the cut "Four Strong Winds". It is also a great cut to judge voicing. You'll know when it's right.
 

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I don't want to besmirch Brian's name as he is no longer here to defend his speakers, but.....I used to go to CES with my friend Brooks Berdan (who has also recently passed away) every January. I visited the VMPS room every year, and every year I would hear the same thing: SPL waaaay too high for the room, and piercingly shrill highs. The combination of those two alone would have driven me from the room, but there was also the matter of amplifiers obviously being driven into hard clipping. :eek: Yow! Brian seemed to be oblivious to anything being wrong, and I would look at him and wonder if listening at these SP levels for who knows how many years had damaged his hearing. But that doesn't answer how he rationalized the measurements.
 

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Anyone who has heard Brooks' beautiful and painstaking setups of Wilson speakers in his showroom knows what the difference can be. I am not sure Brian ever measured anything and Danny's graphs kind of confirm it. Brooks was a real class act and we all miss him.
 

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I've had time to get these burned in some now (24/7) and play around a little bit with placement. I can't do a lot with the latter as my wife has busts of David and Diana sitting on top of the speakers..

I thought I heard some cancellations as I moved forward and back through the soundfield, so I thought I would turn the speakers so they pointed straight out, with no toe in.

Wow! I have the rear ports 16" from my padded wall and the incrrease in bass loading jumped way up. It now hits fairly well at 31.5 hz on the test disk. And it will play (softly) to 25hz.

But the big surprise was the soundstage. I thought before it was wide, as I reported in a prior post, but nothing like this. Not just wall to wall, but outside the walls. And the depth opened up to as good or better as when I had them out 38" from the wall.

It sounded so good I hooked it up in two channel with the outboard components. Total transformation. It was so wonderful I watched a couple of movies that way, and the phantom center was so perfect not only did I not miss the center channel speaker, but I forgot about the rear surrounds, which were not playing.

This is a must have upgrade if you have these speakers. And if you do, it is the cheapest path to Nirvana. The unlocked potential in these speakers is amazing. Good as dome tweeters are, there is nothing like a planar mid and ribbon tweeter. You really gotta hear this one!
 
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